STM32F411: Enable all GPIO-clocks in SystemInit()

Serial pins are also there.

cmsis-system_stm32f4xx.c

@@ -209,6 +209,13 @@ void SystemInit(void)
   /* Configure the System clock source, PLL Multiplier and Divider factors,
      AHB/APBx prescalers and Flash settings */
   SetSysClock();
+
+  // Enable power and clocking for all GPIO
+  RCC->AHB1ENR |= RCC_AHB1ENR_GPIOAEN | \
+                  RCC_AHB1ENR_GPIOBEN | \
+                  RCC_AHB1ENR_GPIOCEN | \
+                  RCC_AHB1ENR_GPIODEN | \
+                  RCC_AHB1ENR_GPIOHEN;
  
 }
 

serial-stm32.c

@@ -22,8 +22,6 @@
 
 void serial_init()
 {
-    // Enable TX/RX clock (GPIOA)
-    RCC->AHB1ENR |= RCC_AHB1ENR_GPIOAEN;
     // Enable USART2 clock
     RCC->APB1ENR |= RCC_APB1ENR_USART2EN;